In the bread-making trade, freeze-storage dough (frozen dough) is widely used as a means for the rationalization of production. Very high energy costs are required for freezing, freeze-storage, freeze-transportation, thawing, etc. In order to reduce these energy costs, a dough which is capable of being stored through refrigeration is used [Report by Katsuro Kaitaku Chosa Kenkyu Jigyo (active development investigation project), 36-45 (1990); B & C, 26-37 (1990); Basic Knowledge for New Bread Making, 148-180 (Jul. 10, 1988, 7th edition)]. However, the dough capable of being stored through refrigeration poses a problem with respect to the storage stability of the yeast contained in the dough, because the yeast deteriorates during the long-term storage.
Further, fat and oil such as butter, margarine, etc. are folded into the dough in the production of a Danish pastry, croissants, etc., and the uniform layers of the dough and the fat and oil are indispensable to making a good product. To satisfy this requirement, the folding of the fat and oil is ordinarily conducted batchwise. In each batchwise operation, increase in the temperature of the dough and the temperature of the fat and oil affects the extensions of the dough and the folded fat and oil. For this reason, a so-called retarding method is employed in which the freezing is repeatedly carried out in a refrigerator. With the ordinary yeast, fermentation proceeds, and thus the remaining activity of the yeast is lowered at the time when the fermentation is completed. In addition to the deterioration of the yeast due to the storage through refrigeration, the bread making by the retarding method involves a lot of problems.
Still further, when an ordinary yeast is contained in a refrigeration-storage dough for a domestic purpose (which is mostly packed in a sealed container), the refrigeration-storage dough has no storage stability and therefore the dough is degraded. In order to prevent the degradation of the dough, a chemical foaming agent is used instead of the yeast in many cases. Nevertheless, such a dough cannot give a satisfactory bread product in regard to flavor, appearance, etc.